1. Field of the Invention
The present invention relates generally to machines and methods for forming and sealing envelopes, and more particularly to a machine for folding and inserting disks into floppy disk envelopes.
2. Description of the Prior Art
Envelopes used for encasing floppy disks are typically formed from a plastic film material having a non-woven fabric liner for protecting the disk media. Heretofore, such envelopes have been folded from pre-cut envelope blanks which are transported individually among various folding and sealing stations on one or more folding machines. Frequently, a first folding apparatus is provided for transversely folding the envelope blank in half and sealing two flaps along the sides, leaving an open end opposite the transverse fold. The partially folded envelope is then taken to a second apparatus where the disk media is inserted and the end envelope flap folded and sealed.
The manipulation of single pre-cut envelope blanks presents a number of problems. The blanks must be advanced sequentially among various folding, disk insertion, and sealing stations, usually requiring complex systems of grippers and suction devices. Moreover, intermachine transfers are most often accomplished manually, requiring labor and often slowing down the folding process. The most serious drawback with the prior art folding machines, however, has been the difficulty in properly aligning the envelope blanks so that the dimensions of the resulting envelopes are precisely controlled.
Because the envelope holds the disk in place while the disk is being read, it is important that the dimensions of the jacket be maintained within very close tolerances. It is also critical that the folds be made accurately in order to assure that the folded envelope remains absolutely flat after the folds have been sealed. The task of forming these envelopes is further complicated when envelope holes are pre-cut envelope blanks. The holes in such pre-cut envelope blanks must be accurately aligned after folding is complete. Any misalignment of the envelope blank might render the final folded product useless.
Because of these requirements, complex aligning systems have been provided in prior art machines to assure that the envelope blank is properly positioned at each folding station. Most commonly, prior art machines utilize one or more flat mandrels for holding the envelope blank while it is folded in half and while the side flaps are sealed. The mandrel acts as a form and the jacket is folded around the mandrel. While this approach is generally workable, any slight misalignment of the equipment will result in misshaped envelopes. Moreover, the mandrels are frequently used to transport the partially folded envelope blank to a gluing or heat sealing station, thus preventing insertion of disk media during the envelope folding operation.
In view of the above, it would be desirable to develop novel methods and systems for forming floppy disk envelopes in a manner which assures proper alignment of fold lines in the final product. It would be particularly desirable if such methods and systems allowed for insertion of the disk media into the envelope during the forming process and complete sealing of the envelope before the formed product was discharged from the machine.